Following options will also help you to reduce the reactor differential pressure;
1. Feed filter also plays an important role. If feed filter are working properly then Reactor differential pressure will be under control. Normally, up to 25 micron size particles are removed by the feed filters.
2. Feed Gas flow also takes part in reactor differential pressure. Use the option of compressor spill back or compressor load or reduce RPM (Centrifugal Compressor) to optimize the gas flow to minimum required flow. So that Hydrogen to Hydrocarbon ratio is within required range.
3. Use maximum straight run diesel or lighter feed and avoid heavy cracked feed.